Modulation of mitochondrial Ca2+ in ECV304 endothelial cells by agents which elevate cAMP.
In the human umbilical vein endothelial cell-derived cell line, ECV304, we have previously shown that the elevation of [Ca2+]m in response to agonist stimulation is dependent on Ca2+ influx, i.e. an ATP-induced sustained increase in [Ca2+]c results in a slow-onset, sustained elevation in [Ca2+]m [Lawrie A.M., Rizzuto R., Pozzan T., Simpson A.W.M. A role for calcium influx in the regulation of mitochondrial calcium in endothelial cells. J Biol Chem 1996; 271: 10753-10759]. In this study, we have investigated the effect of raising cAMP on ATP-evoked elevations in both [Ca2+]m and [Ca2+]c by: (i) activating adenylate cyclase with the forskolin analogue--forskolin 6-[3'-(N,N-dimethylaminopropionyl)]-HCl (1 microM) (FA); (ii) addition of membrane permeable dibutyryl-cAMP (100 microM) (dbcAMP); and (iii) a combination of FA plus inhibition of cAMP phosphodiesterase using RO-20-1724 (17.5 microM) (RO);. We have found that protocols aimed at elevating cAMP significantly reduce the ATP-evoked (1-10 microM) rise in [Ca2+]m (n = 14); however, the [Ca2+]c response to ATP was not affected (n = 33). This new evidence shows that a second messenger system, other than Ca2+ itself, may influence [Ca2+]m changes in response to agonist stimulation.
Lawrie
A M
AM
Department of Human Anatomy and Cell Biology, University of Liverpool, UK. a.m.lawrie@abdn.ac.uk
Zolle
O
O
Simpson
A W
AW
D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone / Q000494:pharmacology; D003994:Bucladesine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002460:Cell Line; D005576:Colforsin / Q000031:analogs & derivatives / Q000494:pharmacology; D000242:Cyclic AMP / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism*; D010726:Phosphodiesterase Inhibitors / Q000494:pharmacology
D010726:Phosphodiesterase Inhibitors; D005576:Colforsin; D012368:4-(3-Butoxy-4-methoxybenzyl)-2-imidazolidinone; D003994:Bucladesine; D000242:Cyclic AMP; D002118:Calcium